Hindered piperidine carboxylic acids, metal salts thereof and stabilized compositions

ABSTRACT

Compounds having the formula ##STR1## WHEREIN R 1  and R 2  are lower alkyl or cycloalkyl, 
     R 3  is hydrogen, alkyl, methoxyethyl, alkenyl,  propargyl, benzyl or alkyl substituted benzyl, 
     R 4  is alkylene, alkyl-thio-alkyl or alkyl-oxo-alkyl, 
     M is hydrogen or a metal, and 
     z has a value of from 1 to 4, 
     Are good light stabilizers. The carboxylic acids are prepared, for example, from 2,2,6,6-tetramethyl-piperidin-4-ol and sebacic acid to give o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate. The metal salts of the acids are readily prepared by reacting the acids or their salts with a reactive form of the metal or metal complex.

BACKGROUND OF THE INVENTION

This is a division of application Ser. No. 429,232 filed on Dec. 28,1973, now U.S. Pat. No. 3,920,661.

This invention relates to the stabilization of organic material normallytending to deteriorate. In particular, the invention relates to theprotection of synthetic polymers against the harmful degradativeeffects, such as discoloration and embrittlement caused by exposure tolight, especially ultraviolet light.

It is known that actinic radiation, particularly in the near ultravioletregion, has a deleterious effect on both the appearance and propertiesof organic polymers. For example, normally colorless or light coloredpolyesters yellow on exposure to sunlight as do such cellulosics ascellulose acetate. Polystyrene discolors and cracks, with accompanyingloss of its desirable physical properties when exposed to actinic light,while vinyl resins, such as polyvinyl chloride and polyvinyl acetatespot and degrade. The rate of air oxidation of polyolefins such aspolyethylene and polypropylene is materially accelerated by ultravioletlight.

It has been proposed to stabilize polymeric materials againstultraviolet light deterioration by the use of various types ofultraviolet absorbers. Thus, U.S. Pat. No. 3,004,896 discloses for thispurpose 2(2-hydroxyphenyl)benzotriazole derivatives, while U.S. Pat. No.3,189,630 discloses certain metal salts of hydroxybenzoic acids whichare useful as actinic stabilizers in synthetic polymers.

Additionally, in U.S. Pat. No. 3,120,540 there is discussed the reactionof substituted 4-piperidinol compounds with acid anhydrides having theformula ##STR2## where n is 1 to 4, to yieldbis(polymethyl)-4-piperidinol alkanoates. In the example of this patentthe probable formation of ##STR3## is mentioned as an intermediate inthe synthesis of the bis(hydrogen sulfate)salt ofbis(1,2,2,6,6-pentamethyl-4-piperidyl)succinate. The compounds of U.S.Pat. No. 3,120,540 are taught to possess significant pharmacologicalactivity in lowering blood pressure. We have now found that certain acidhalf esters of hindered piperidines stabilize organic substrates againstthe degradative effect of ultraviolet light and that the degree ofstabilization achieved is significantly greater in the case of higheracid half esters than in the case of the above-mentioned succinic acidhalf-ester. We have also found that certain hetero-atom containingpiperidine half-esters and salts of piperidine half esters are useful asstabilizers of organic materials.

DETAILED DISCLOSURE

The present invention is accordingly directed to a new class ofultraviolet light stabilizers which consist of a compound of the formula##STR4## wherein

R₁ and R₂ independently of each other are straight- or branched-chainalkyl having from 1 to 6 carbon atoms, or together with the carbon towhich they are bound form a cyclopentyl or cyclohexyl ring, which isunsubstituted or substituted with a methyl group,

R₃ is hydrogen, alkyl having 1 to 12 carbon atoms, β-methoxyethyl,alkenyl having 3 to 4 carbon atoms, propargyl, benzyl or alkylsubstituted benzyl,

R₄ is straight or branched-chain alkylene having 5 to 8 carbon atoms, orthe group

    (CH.sub.2).sub.m Y(CH.sub.2).sub.n

wherein Y is oxygen or sulfur and m and n independently of each otherare an integer from 1 to 3,

M is hydrogen or a metal selected from the group consisting of barium,nickel, manganese, calcium, zinc, iron, sodium, cobalt tin and dialkyltin, and

z has a value of from 1 to 4, the value of z being the same as theavailable valence of M.

Examples of R₁ and R₂ are methyl, ethyl, iso-propyl, n-butyl andn-hexyl. Preferably, R₁ and R₂ are each a methyl group. Representativeof R₁ and R₂ as cycloalkyl groups are cyclohexyl, cyclopentyl, 2-methyl,3-methyl and 4-methylcyclohexyl, and 2-methyl and 3-methylcyclopentyl.The preferred cycloalkyl groups are cyclohexyl and 2-methylcyclohexyl.Most preferably, R₁ and R₂ are each a methyl group.

Substituent R₃ can be hydrogen, alkyl having 1 to 12 carbon atoms,preferably alkyl having 1 to 4 carbon atoms, methyl being particularlypreferred, β-methoxyethyl, alkenyl having 3 to 4 carbon atoms,preferably allyl, propargyl, benzyl or alkyl substituted benzyl.Hydrogen and methyl are particularly preferred.

Examples of R₃ are hydrogen, methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, n-hexyl, n-octyl, n-dodecyl, alkyl, α-methallyl,propargyl, benzyl, α-methylbenzyl, p-methylbenzyl and α,p-dimethylbenzyl.

The preferred alkylene residue R₄ is straight-chain alkylene having 5 to8 carbon atoms, or the group (CH₂)_(m) Y(CH₂)_(n) wherein Y is oxygen orsulfur and m and n independently of each other are 1 or 2.

Among the substituents represented by M, hydrogen, nickel and manganeseare preferred. Particularly preferred are hydrogen and nickel.

This invention also relates to compositions of matter which arestabilized against ultraviolet light deterioration which comprises asynthetic organic polymer normally subject to ultraviolet deteriorationcontaining from about 0.005% to 5% by weight of the polymer of thecompounds of formula I and preferably from 0.01 to 2% by weight.

The compounds as represented by formula I, can be used in combinationwith other light stabilizers such as 2(2-hydroxyphenyl)benzotriazoles,2-hydroxybenzophenones, nickel complexes and benzoates.

The compounds of this invention are stabilizers of organic materialnormally subject to thermal, oxidative or actinic light deterioration.Materials which are thus stabilized include synthetic organic polymericsubstances including homopolymers, copolymers, and mixtures thereof,such as vinyl resins formed from the polymerization of vinyl halides orfrom the copolymerization of vinyl halides with unsaturatedpolymerizable compounds, e.g., vinyl esters, α,β-unsaturated acids,α,β-unsaturated esters, α,β-unsaturated ketones, α,β-unsaturatedaldehydes and unsaturated hydrocarbons such as butadienes and styrene;poly-α-olefins such as high and low density polyethylene, cross-linkedpolyethylene, polypropylene, poly(4-methylpentane-l and the like,including copolymers of α-olefins; such as ethylene-propylenecopolymers, and the like; dienes such as polybutadiene, polyisoprene,and the like, including copolymers with other monomers; polyurethanessuch as are prepared from polyols and organic polyisocyanates, andpolyamides such as polyhexamethylene adipamide and polycaprolactam;polyesters such as polyethylene terephthalates; polycarbonates such asthose prepared from bisphenol-A and phosgene; polyacetals such aspolyethylene terephthalate polyacetal; polystyrene, polyethyleneoxide;polyacrylics such as polyacrylonitrile; polyphenyleneoxides such asthose prepared from 2,6-dimethylphenol and the like; and copolymers suchas those of polystyrene containing copolymers of butadiene and styreneand those formed by the copolymerization of acrylonitrile, butadieneand/or styrene.

Other materials which can be stabilized by the compounds of the presentinvention include lubricating oil of the aliphatic ester type, i.e.,di(1,2-ethylene)-azelate, pentaerythritol tetracaproate, and the like;animal and vegetable derived oils, e.g., linseed oil, fat, tallow, lard,peanut oil, cod liver oil, castor oil, palm oil, corn oil, cottonseedoil, and the like; hydrocarbon materials such as gasoline, mineral oil,fuel oil, drying oil, cutting fluids, waxes, resins, and the like, saltsof fatty acids such as soaps and the like; and alkylene glycols, e.g.,β-methoxyethyleneglycol, methoxytriethyleneglycol, triethylene glycol,octaethyleneglycol, dibutyleneglycol, dipropyleneglycol and the like.

The compounds of this invention are particularly useful as UV lightstabilizers, especially for the protection of polyolefins, for instance,polyethylene, polypropylene, poly(butene-1), poly(pentene-1), poly(3-methylbutene-1), poly(4-methylpentene-1), various ethylene-propylenecopolymers and the like.

In general, the stabilizers of this invention are employed from about0.01 to about 5% by weight of the stabilized composition, although thiswill vary with the particular substrate and application. An advantageousrange is from about 0.05 to about 2% and especially 0.1 to about 1%.

For addition to polymeric substrates, the stabilizers can be blendedbefore polymerization or after polymerization, during the usualprocessing operations, for example, by hot-milling, the composition thenbeing extruded, pressed, blow molded or the like into films, filaments,hollow spheres and the like. The heat stabilizing properties of thesecompounds may advantageously stabilize the polymer against degradationduring such processing at the high temperature generally encountered.The stabilizers can also be dissolved in suitable solvents and sprayedon the surface of films, fabrics, filaments or the like to provideeffective stabilization. Where the polymer is prepared from a liquidmonomer as in the case of styrene, the stabilizer may be dispersed ordissolved in the monomer prior to polymerization or curing.

These compounds can also be used in combination with other additivessuch as antioxidants, sulfur-containing esters such asdistearyl-β-thiodipropionate (DSTDP), dilauryl-β-thiodipropionate(DLTDP) in an amount of from 0.01 to 2% by weight of the organicmaterial, and the like, pourpoint depressants, corrosion and rustinhibiotors, dispersing agents, demulsifiers, antifoaming agents,fillers such as glass or other fibers, carbon black, accelerators andthe other chemicals used in rubber compounding, plasticizers, colorstabilizers, di- and tri-alkyl- and alkylphenylphosphites, heatstabilizers, ultraviolet light stabilizers, antiozonants, dyes,pigments, metal chelating agents, dyesites and the like. Oftencombinations such as these, particularly the sulfur containing esters,the phosphites and/or the ultraviolet light stabilizers will producesuperior results in certain applications to those expected by theproperties of the individual components.

The following formula represents co-stabilizers which are in certaininstances very useful in combination with the stabilizers of thisinvention: ##STR5## wherein R is an alkyl group having from 6 to 24carbon atoms; and n is an integer from 1 to 6. Especially usefulcompounds of this type are dilauryl-β-thiodipropionate anddistearyl-β-thiodipropionate. The above co-stabilizers are used in theamount of from 0.01 to 2% by weight of the organic material, andpreferably from 0.1 to 1%.

Although the compounds of this invention may to some degree also beeffective as thermal stabilizers, if the processing of the polymer iscarried out at high temperatures it is advantageous to incorporateadditional antioxidants.

In most applications, it is desirable to incorporate into the resincomposition, sufficient thermal antioxidants to protect the plasticagainst thermal and oxidative degradation. The amount of antioxidantrequired will be comparable to that of the actinic stabilizer. Namely,from about 0.005% to 5% and preferably from 0.01% to 2% by weight.Representative of such antioxidants are phosphite esters, such astriphenylphosphite and dibutylphosphite and alkyl arylphosphites such asdibutylphenylphosphite, and the like.

The best results have been obtained with the preferred class of thermalantioxidants, the hindered phenols. These compounds have been found toprovide the best thermal stabilization with the least discoloration inthe compositions of the invention. Amoung these phenolic antioxidantsare included the following:

di-n-octadecyl(3-5-butyl-4-hydroxy-5-methylbenzyl)malonate

2,6-di-t-butylphenol

2,2'-methylene-bis(6-t-butyl-4-methylphenol)

2,6-di-t-butylhydroquinone

octadecyl-(3,5-di-t-butyl-4-hydroxybenzylthio)acetate

1,1,3-tris(3-t-butyl-6-methyl-4-hydroxyphenyl)butane

1,4-bis(3,5-di-t-butyl-4-hydroxybenzyl)-2,3-5,6-tetramethylbenzene

2,4-bis-(3,5-di-t-butyl-4-hydroxyphenoxy)-6-(n-octylthio)-1,3,5-triazine

2,4-bis-(4-hydroxy-3,5-di-t-butylphenoxy)-6-(n-octylthioethylthio)-1,3,5-triazine

2,4-bis-(n-octylthio)-6-(3,5-di-t-butyl-4-hydroxyanilino)-1,3,5-triazine

2,4,6-tris-(4-hydroxy-3,5-di-t-butylphenoxy)-1,3,5-triazine

n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl) propionate

n-octadecyl-3,5-di-t-butyl-4-hydroxybenzoate

2-(n-octylthio)ethyl-3,5-di-t-butyl-4-hydroxybenzoate

stearamido N,N-bis-{ethylene3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}

1,2-propylene glycol bis-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}

pentaerythritol tetrakis-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}

dioctadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate

di-n-octadecyl-1-(3,5-di-t-butyl-4-hydroxyphenyl)-ethanephosphonate

The above phenolic hydrocarbon stabilizers are known and many arecommercially available.

The above antioxidants have been listed only for the purpose ofillustration and it is important to note that any other antioxidant canbe employed with similar improved results. The above exemplifiedantioxidants and other related antioxidants which are incorporatedherein by reference, are disclosed in greater detail in the followingpatents: Netherlands Pat. No. 67/1119, issued Feb. 19, 1968; NetherlandsPat. No. 68/03498 issued Sept. 18, 1968; U.S. Pat. Nos. 3,255,191;3,330,859, 3,644,482, 3,281,505; 3,531,483, 3,285,855; 3,364,250;3,368,997; 3,357,944 and 3,758,549.

The compounds of this invention may be prepared by reacting apiperidinol of the formula. ##STR6## wherein R₁, R₂, and R₃ are asdefined above via a usual esterifcation procedure with a diacid of theformula ##STR7## wherein R₄ is as defined above, or conveniently with aacid anhydride in the case of diglycolic anhydride and the like. In theprocess of reacting an acid of formula III with a compound of formula IIthe esterification catalyst is preferably a neutral catalyst, forinstance a tetraalkyl titanate.

The acids and acid anhydrides which are reacted with the compounds offormula II may be prepared by methods well known in the art.

The metal salts of the present invention can be prepared by treating thehindered piperidine carboxylic acids of formula I with a reactive formof the metal or metal complex, e.g., sodium hydroxide or the like.Alternatively, and preferably in the case of metal complexes and metalsother than the alkali metals, a double decomposition is employed. Thus,for example, a sodium salt of the present invention is treated withnickel chloride. In a similar fashion use of other halides such asmanganese dichloride, barium chloride and the like results in formationof the corresponding metal derivative.

The compounds of formula II may be prepared according to procedurespresented in patent application Ser. No. 408,123, filed Oct. 19, 1973.

The following examples, presented for illustration and not limitation,will further serve to typify the nature of the present invention.

EXAMPLE 1 O-mono-(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate

A. In a 3 liter 3-necked flask equipped with a stirrer, thermometer,condenser with water separator and drying tube, and nitrogen inlet tubewere placed a mixture of 161.6 g (0.8 moles) of sebacic acid, 50.4 g(0.32 moles) of 2,2,6,6-tetramethylpiperidin-4-ol and 2000 ml of xylene.To the mixture was added 9.6 ml (0.032 moles) of tetraisopropyltitanate. The reaction mixture was heated under reflux with stirring and6.0 ml of water were collected over a 30 hour period. The reactionmixture was cooled and the xylene was removed by decantation. Theresidue was recrystallized from warm dimethylformamide, then fromisopropanol, yielding 26.9 g of white crystals, m.p. 174° to 178° C ofthe desired material.

B. By following the above procedure (A), and substituting for thesebacic acid an equivalent amount of:

a. pimelic acid

b. tetramethyl succinic acid

c. azelaic acid

d. thiodipropionic acid

e. suberic acid

f. thiodiglycolic acid

there is respectively obtained the following compounds:

a. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)pimelate

b. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)tetramethyl succinate

c. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)azelate

d. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)thiodipropionate

e. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)suberate

f. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)thiodiglycoate.

C. By essentially following the above procedure (A), and substitutingthe reactants appropriate quantities of the following reagents

a. 1-n-dodecyl-2,2,6,6-tetramethyl piperidin-4-ol and sebacic acid

b. 1-benzyl-2,2,6,6-tetramethyl piperidin-4-ol and azelaic acid

c. 1-allyl-2,2,6,6-tetramethyl piperidin-4-ol and suberic acid there arerespectively obtained and following compounds:

a. o-mono(1-n-dodecyl-2,2,6,6-tetramethylpiperidin-4-ol)sebacate.

b. o-mono(1-benzyl-2,2,6,6-tetramethyl piperidin-4-ol) azelate.

c. o-mono(1-allyl-2,2,6,6-tetramethyl piperidin-4-ol) suberate.

EXAMPLE 2 O-mono(1,2,2,6,6-pentamethyl-piperidyl-4)diglycolate

In a 1 liter 3-necked flask equipped with a stirrer, thermometer,condenser with water separator and drying tube, and nitrogen inlet, wasplaced 18.93 g (0.10 moles) of 1,2,2,6,6-pentamethyl-piperidine-4-olmonohydrate and 500 ml of xylene. The reaction mixture was heated underreflux with stirring until 1.8 ml of water had been collected in thewater separator. The reaction mixture was cooled to 40° C and 11.6 g(0.10 moles) of diglycolic anhydride were added. The reaction mixturewas heated slowly to reflux. The anhydride appeared to go into solution;then a precipitate was noted. The reaction mixture was heated underreflux for 4 hours and allowed to cool overnight. The precipitatedsolids were collected by suction, washed with hexane and dried in air.The product was recrystallized from ethanol-isopropanol, and dried undervacuum at 60° C over P₂ O₅, yielding 14.7 g of colorless crystals, m.p.194°-198° C, of the desired material.

EXAMPLE 3 Nickelbis(o-mono-(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate)

A. In a 2 liter 3-necked flask equipped with a thermometer, droppingfunnel, stirrer and nitrogen inlet were placed 20.49 g (0.06 moles) ofo-mono(2,2,6,6-tetramethylpiperidin-4-ol)sebacate and 1200 ml ofabsolute methanol. To the mixture was added via pipette 60 ml of 1 N KOHin methanol. To the clear solution was then added a solution of 7.13 g(0.03 moles) of NiCl₂ 6H₂ O in 120 ml of absolute methanol over a 10minute period. The reaction mixture was stirred at room temperature for1 hour and at 50° C for 1 hour. The green methanolic solution was thenevaporated under reduced pressure and 1200 ml of isopropanol was added.The isopropanol solution was heated to 50° C for 1 hour and allowed tostand overnight. The isopropanol solution was filtered with suction andthe filtrate evaporated under reduced pressure. The residue was treatedwith 850 ml of benzene, filtered with suction, and the benzene solutionevaporated under reduced pressure and dried at 70° C under vacuum,yielding 18.5 g of a pale green glassy solid of the desired material.

B. By following the above procedure (A) and substituting for theo-mono-(2,2,6,6-tetramethylpiperidin-4-ol)sebacate an equivalent amountof:

a. o-mono-(2,2,6,6-tetramethyl-piperidin-4-ol)pimelate

b. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)tetramethyl succinate

c. o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)thiodiglycolate

d. o-mono(1-n-dodecyl-2,2,6,6-tetramethyl-piperidin-4-ol)sebacate

e. o-mono(1-benzyl-2,2,6,6-tetramethyl piperidin-4-ol)azelate

f. o-mono(1-allyl-2,2,6,6-tetramethyl piperidin-4-ol)suberate.

There is respectively obtained the following compounds:

a. nickel complex of o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)pimelate

b. nickel complex ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)tetramethyl succinate

c. nickel complex ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)thiodiglycolate.

d. nickel complex of o-mono(1-n-dodecyl-2,2,6,6-tetramethylpiperidin-4-ol)sebacate

e. nickel complex of o-mono(1-benzyl-2,2,6,6-tetramethylpiperidin-4-ol)azelate

f. nickel complex of o-mono(1-allyl-2,2,6,6-tetramethylpiperidin-4-ol)suberate.

EXAMPLE 4

By essentially following the procedure of Example 3 (A) and substitutingthe following metal complexes for nickel chloride:

a. manganese chloride

b. zinc chloride

c. ferric chloride

d. cobalt (ous) chloride

there is thus respectively obtained:

a. manganese complex of bis{O-mono(2,2,6,6-tetramethylpiperidin-4-ol)sebacate}

b. zinc complex ofbis{o-mono(2,2,6,6-tetramethylpiperidin-4-ol)sebacate}

c. iron complex ofbis{o-mono(2,2,6,6-tetramethylpiperidin-4-ol)sebacate}

d. cobalt comples ofbis{o-mono(2,2,6,6-tetramethylpiperidin-4-ol)sebacate}.

EXAMPLE 5 Ni (II)bis{o-mono-(1,2,2,6,6-Pentamethylpiperidin-4-ol)diglycolate}

In a 100 ml 1-necked flask equipped with a magnetic stirrer anddistillation head were placed 2.87 g (0.01 moles) ofo-mono-(1,2,2,6,6-tetramethylpiperidin-4-ol)diglycolate, 1.26 g (0.005moles) of nickel acetate tetrahydrate and 50 ml of water. The reactionmixture was heated slowly to distillation temperature. The distillatecollected was assayed by titration with 0.1 N KOH with phenophthalein asindicator. The distillation was continued until 98% of the theoreticalamount of acetic acid had been collected. The reaction mixture was thenevaporated under vacuum, and the residue dissolved in methanol, filteredand the filtrate evaporated under reduced pressure. The green powderyresidue, m.p. 210° (d) weighed 3.28 g and proved to be the desiredmaterial.

EXAMPLE 6 ARTIFICIAL LIGHT EXPOSURE TEST

Deterioration of most polymers caused by ultraviolet light is so slow atambient temperatures, even in the absence of stabilizers, that testingof the effects of stabilizers generally must be conducted either athigher temperatures or in an accelerated artificial light exposuredevice in order to yield results in a convenient period of time. Thetests conducted on polymers using an artificial light exposure device isdescribed below:

a. Sample Preparation

5 mil Film - Unstabilized polypropylene powder (Hercules Profax 6501) isthoroughly blended with the indicated amounts of additives. The blendedmaterial is then milled on a 2 roll mill for 5 minutes at 182° C. Themilled sheet is then compression molded at 220° C into 5 mil thick filmunder a pressure of 175 psi and water cooled in the press.

b. Testing Method

This test is conducted in a FS/BL unit, basically of the AmericanCyanamid design, which consists of 40 tubes of alternating fluorescentsunlamps and black lights (20 of each). The 5 mil sample film which aremounted on 3 × 2 inch IR card holders with 1/4 × 1 inch windows and areplaced on a rotating drum 2 inches from the bulbs in the FS/BL unit. Thetime in hours is noted for the development of 0.5 carbonyl absorbanceunits as determined on an Infrared Spectophotometer. The development ofcarbonyl functional groups in the polymer is proportional to the amountof degradation caused by the ultraviolet light exposure.

The test results reported below were obtained according to theprocedures described above. The amounts of the additives are expressedin weight percent based on the weight of the polymer.

                  TABLE I                                                         ______________________________________                                        Light Stabilization Data in                                                   Polypropylene                                                                 ______________________________________                                                     Time in Hours to                                                              0.5 Carbonyl Absorbance Units                                    Additive       Formulation A*                                                                             Formulation B**                                   ______________________________________                                        o-mono(2,2,6,6-tetra-                                                         methylpiperidin-4-ol)                                                         sebacate       2330         2495                                              nickel bis{o-mono(2,2,                                                        6,6-tetramethylpiperidin-                                                     4-ol)sebacate} 3635         2335                                              o-mono(1,2,2,6,6-penta-                                                       methyl piperidin-4-ol)                                                        diglycolate    1295         1420                                              nickel bis{o-mono(1,2,2,                                                      6,6-pentamethyl piperidin-                                                    4-ol)diglycolate}                                                                             565         1125                                              Blank           215         --                                                ______________________________________                                          *Formulation A contains 0.5% additive and 0.2% antioxidant dioctadecyl       3,5-di-t-butyl-4-hydroxybenzylphosphonate.                                    **Formulation B contains 0.25% additive, 0.25% UV absorber                    2(2'-hydroxy-3',5'-di-t-butyl-phenyl)-5-chlorobenzotriazole, and 0.2%         antioxidant dioctadecyl 3,5-di-t-butyl-4-hydroxybenzyl-phosphonate.           Proportionately good stabilization is obtained when in the Compositions o     Table I the compounds of this invention are present in the concentrations     of 0.1% and 1%.                                                          

Other hindered phenolic antioxidants may be used in place ofdi-octadecyl(3,5-di-t-butyl-4-hydroxybenzyl)phosphonate in the abovementioned compositions for example, di-n-octadecylα-(3-t-butyl-4-hydroxy-4-methylbenzyl)malonate,2,4-bis(n-octylthio)-6-(3,4-di-t-butyl-4-hydroxyaniline)-1,3,5-triazine,octadecyl 3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate,pentaerythritol-tetrakis{3-(3,5-di-t-butyl-4-hydroxyphenyl)}propionate,tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,2,6-di-tert-butyl-4-methylphenol,N,N,N-tris-(3,5-di-tert-butyl-4-hyroxybenzyl)isocyanurate, and2,4,6-tris(3,5-di-tert-butyl-4-hyroxybenzyl)-1,3,5-trimethylbenzyl.

The compositions of Table I are also stabilized with2(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole is replacedwith the following UV absorbers:

a. 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate

b. 2-hydroxy-4-n-octoxybenzophenone

c. {2,2'-thiobis(4-t-octylphenolate)}-n-butylamine nickel II

d. p-octylphenyl salicylate

e. 2,2'-dihydroxy-4,4'-dimethoxybenzophenone

f. 2(2'-hydroxy-5'-methylphenyl)-benzotriazole.

EXAMPLE 7

High impact polystyrene resin containing elastomer (i.e.,butadiene-styrene) is stabilized against loss of elongation propertiesdue to exposure to ultraviolet light by incorporation of 0.3% by weightof o-mono-(2,2,6,6-tetramethylpiperidin-4-ol)sebacate.

The unstabilized resin is dissolved in chloroform and the stabilizerthen added, after which the mixture is cast on a glass plate and thesolvent evaporated to yield a uniform film which, upon drying, isremoved and cut up, and then pressed for 7 minutes at a temperature of163° C and a pressure of 2,000 pounds per square inch into a sheet ofuniform thickness (25 mil). The sheets are then cut into stripsapproximately 4 × 0.5 inches. A portion of these strips is then measuredfor percent of elongation in the Instron Tensile Testing Apparatus(Instron Engineering Corporation, Qunicy, Mass.). The remaining portionsof the strips are placed in an FS/BL chamber according to Example 6(B)except that the samples are mounted and white cardboard stock and thetime to 50% reduction in elongation is measured. The stabilizedpolystyrene resin retains its elongation property longer than theunstabilized resin.

EXAMPLE 8

Unstabilized linear polyethylene is solvent blended in methylenechloride with 0.5% by weight of the substrate of the nickel complex ofo-mono(2,2-6,6-tetramethylpiperidin-4-ol)sebacte and then vacuum dried.The resin is then extrusion compounded on a 1 inch 24/1=L/D extruder,melt temperature 450° F (232° C) and pressed for 7 minutes at atemperature of 163° C and a pressure of 2000 psi into a sheet of uniformthickness of 100 mil. The sheets are then cut into plaques of 2 inch × 2inch. The plaques are then exposed in a FS/BL exposure device and colormeasurements made periodically using a Hunter Color Difference MeterModel D25. Polyethylene stabilized with the above compound is found tobe much more stable than the unstabilized polyethylene or thepolyethylene stabilized only with an antioxidant. EXAMPLE 9

A quantity of SBR emulsion containing 100 g of rubber (500 ml of 20% SBRobtained from Texas U.S., Synpol 1500) previously stored under nitrogen,is placed in a beaker and stirred vigorously. The pH of the emulsion isadjusted to 10.5 with a 0.5N NaOH solution.

To the emulsion is added 50 ml of 25% NaCl solution. A 6% NaCl solutionadjusted with hydrochloric acid to a pH 1.5 is added in a thin streamwith vigorous stirring. When pH 6.5 is reached, the rubber begins tocoagulate and the addition is slowed down in order to maintain uniformagitation. The addition of the acidic 6% NaCl solution is terminatedwhen a pH 3.5 is reached. The coagulated crumb-rubber slurry at pH 3.5is stirred for 1/2 hour.

The coagulated rubber is isolated by filtration through cheese cloth,and rinsed with distilled water. After three subsequent washings withfresh distilled water, the coagulated rubber is dried, first at 25 mm Hgand finally to constant weight under high vacuum (>1 mm) at 40°-45° C.

The dried rubber (25 g) is heated under nitrogen at 125° C in aBrabender mixer and to this is added with mixing 0.25 g (0.5%) ofo-mono(1,2,2,6,6-pentamethyl piperidin-4-ol)diglycolate. is mixed for 5minutes after which it is cooled and compression molded at 125° C into 5× 0.025 inch plaques.

The plaques are exposed to a xenon arc weatherometer and the colormeasurements (L-b) is made after 45, 125 and 290 hours. The samplesstabilized with the above compound are found to be much more lightstable than the unstabilized samples.

EXAMPLE 10

To 50 g of polyacetal resin containing 0.1% of an acid scavenger,dicyandiamide, is added 0.2% by weight of the nickel complex ofo-mono(2,2,6,6-tetramethylpiperidin-4-ol)thiodiglycolate and milled for7 minutes at 200° C in a Brabender Plasti-recorder. The milledformulation is subsequently pressed into a 40 mil sheet at 215° C at 350psi for 90 seconds then cooled quickly in a cold press at 350 psi. Thestabilized sheets are then remolded for 2 minutes at contact pressureand for 3 minutes at 300 psi at 215° C to give plaques 11/2 inch × 21/4inch × 125 mil. Thereafter, the testing procedure of Example 8 isfollowed to determine the light stability of the samples. The stabilizedsamples are found to be much more stable than the unstabilized samples.

EXAMPLE 11

Unstabilized thoroughly dried polyethylene terephthalate chips are dryblended with 1.0% of o-mono(2,2,6,6-tetramethylpiperidin-4-ol)suberate.60/10 denier multifilament is melt spun at a melt temperature of 290° C.The oriented fiber is wound on white cards and exposed in a Xenon ArcFadeometer. Color measurements are made periodically with a Hunter ColorDifference Meter Model D25. The stabilized samples are found to be muchmore light stable than the unstabilized samples.

EXAMPLE 12

a. A composition comprising acrylonitrile-butadiene-styrene terpolymerand 1% by weight of the nickel complex of o-mono(1,2,2,6,6-pentamethylpiperidin-4-ol)diglycolate resists embrittlement due to exposure toultraviolet light longer than one which does not contain the stabilizer.b. A composition comprising polyurethane prepared from toluenediisocyanate and alkylene polyols and 1.0% by weight ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)tetramethyl succinate is morestable to sunlight, fluorescent sunlamps, black lights and fluorescentlights than the unformulated polyurethane. c. A composition comprising apolycarbonate prepared from bisphenol-A and phosgene and 1% by weight ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)pimelate resists discolorationdue to exposure to ultraviolet light longer than one which does notcontain the stabilizer. d. A composition comprisingpolymethyl-methacrylate and 0.25% by weight of the nickel complex ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)azelate resists discolorationdue to exposure to ultraviolet light longer than one which does notcontain the stabilizer.

EXAMPLE 13

a. A stabilized polyamide (nylon 6,6) is prepared by incorporatingtherein 0.1% of o-mono(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate. Thelight stability of the stabilized composition is superior to that of anunstabilized polyamide. b. A stabilized polyphenylene oxide polymer(prepared by polymerizing 2,6-dimethylphenol is prepared byincorporating therein 0.5% by weight of the manganese complex ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate. The stabilizedcompositions resist embrittlement due to exposure to ultraviolet lightlonger than one which does not contain the stabilizer. c. A stabilizedcrystalline polystyrene is prepared by incorporating therein 0.1% byweight of the zinc complex ofo-mono(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate. The stabilizedcomposition resists embrittlement due to exposure to ultraviolet lightlonger than one which does not contain the stabilizer.

Antioxidants may also be incorporated into each of the above mentionedcompositions, for example,di-n-octadecyl-α,α'-bis(3-butyl-4-hydroxy-5-methylbenzyl) malonate2,4-bis(4-hydroxy-3,5-di-t-butylphenoxy)-6-(n-octylthioethylthio)-1,3,5-triazine,2,4-bis(3,5-di-t-butyl-hydroxyphenoxy)-6-(n-octylthio)-1,3,5-triazinedi-n-octadecyl 3(3',5'-di-t-butyl-4-hydroxyphenyl)propionate,respectively.

What is claimed is:
 1. A composition of matter comprising a syntheticorganic polymer normally subject to ultraviolet deterioration stabilizedwith 0.005 to 5% of a stabilizer having the formula ##STR8## wherein R₁and R₂ independently of each other are straight- or branched-chain alkylhaving from 1 to 6 carbon atoms, or together with the carbon to whichthey are bound form a cyclopentyl or cyclohexyl ring, which isunsubstituted or substituted with a methyl group,R₃ is hydrogen, alkylhaving 1 to 12 carbon atoms, β-methoxyethyl, alkenyl having 3 to 4carbon atoms, propargyl, benzyl, or alkyl substituted benzyl, R₄ isstraight- or branched-chain alkylene having 5 to 8 carbon atoms, or thegroup (CH₂)_(m) Y(CH₂)_(n) wherein Y is oxygen or sulfur and m and nindependently of each other are an integer of from 1 to 3, M is hydrogenor a metal selected from the group consisting of barium, nickel,manganese, calcium, zinc, iron, sodium, cobalt, tin and dialkyl tin, andz has a value of from 1 to 4, the value of z being the same as theavailable valence of Msaid stabilizer bing incorporated into thesynthetic organic polymer after polymerization.
 2. The composition ofclaim 1 which contains additionally 0.005 to 5% of a phenolicantioxidant.
 3. The composition of claim 1 which contains additionallya.0.005 to 5% of a phenolic antioxidant, and b. a stabilizing amount of aUV absorber selected from the group consisting of hydroxy benzophenones,hydroxyphenyl benzotriazoles, aromatic esters of salicyclic acid andnickel amine complexes of thiobis-phenols.
 4. The composition of claim 1which contains additionallya. 0.005 to 5% of a phenolic antioxidant, andb. 0.01 to 2% of a thio co-stabilizer of the formula ##STR9## wherein Ris an alkyl group having from 6 to 24 carbon atoms and n is an integerfrom 1 to
 6. 5. The composition of claim 1 wherein the synthetic organicpolymer is a polyolefin.
 6. The composition of claim 5 wherein thepolyolefin is polypropylene.
 7. The composition of claim 5 whichcontains additionally 0.005 to 5% of a phenolic antioxidant selectedfrom the group consisting of n-octadecyl3-(3,5-di-t-butyl-4-hydroxyphneyl propionate,di-n-octadecyl(3,5-di-t-butyl-4-hydroxybenzyl) phosphonate,pentaerythritol-tetrakis[3,5-di-t-butyl-4-hydroxyphenyl)propionate] andtris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate.
 8. The composition ofclaim 5 which contains additionallya. 0.005 to 5% of a phenolicantioxidant selected from the group consisting of n-octadecyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,di-n-octadecyl(3,5-di-t-butyl-4-hydroxybenzyl)phosphonate,pentaerythritol-tetrakis[(3-3,5-di-t-butyl-4-hydroxyphenyl)propionate]and tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, and b. astabilizing amount of a UV absorber selected from the group consistingof 2(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzatriazole,2(2'-hydroxy-5'-methylphenyl)-benzotriazole, and2-hydroxy-4-n-octoxybenzophenone.
 9. The composition of claim 5 whereinR₁ and R₂ are each methyl.
 10. The composition of claim 9 wherein R₄ isstraight-chain alkylene having 5 to 8 carbon atoms, or the group(Ch₂)_(m) Y(Ch₂)_(n) where Y is oxygen or sulfur and m and nindependently of each other are 1 to 2, M is hydrogen, nickel ormanganese, and Z has a value of 1 or
 2. 11. The composition of claim 10wherein M is nickel.
 12. The composition of claim 10 wherein M ishydrogen.
 13. The composition of claim 10 wherein R₄ is straight-chainalkylene having 5 to 8 carbon atoms.
 14. The composition of claim 10wherein R₄ is the group (Ch₂)_(m) Y(CH₂)_(n) is Y, m and n are definedin claim
 24. 15. The composition of claim 5 wherein the stabilizer iso-mono(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate.
 16. The compositionof claim 5 wherein the stabilizer is nickelbis[o-mono(2,2,6,6-tetramethylpiperidin-4-ol) sebacate].
 17. Thecomposition of claim 5 wherein the stabilizer iso-mono(1,2,2,6,6-pentamethyl piperidin-4-ol)diglycolate.
 18. Thecomposition of claim 5 wherein the stabilizer is nickelbis[o-mono(1,2,2,6,6-pentamethylpiperidin-4-ol) diglycolate].
 19. Acompound of the formula ##STR10## wherein R₁ and R₂ independently ofeach other are straight- or branched-chain alkyl having from 1 to 6carbon atoms, or together with the carbon to which they are bound form acyclopentyl or cyclohexyl ring, which is unsubstituted or substitutedwith a methyl group.R₃ is hydrogen, alkyl having 1 to 12 carbon atoms,β-methoxyethyl, alkenyl having 3 or 4 carbon atoms, propargyl, benzyl,or alkyl substituted benzyl, R₄ is straight- or branched-chain alkylenehaving 5 to 8 carbon atoms, or the group (CH₂)_(m) Y(CH₂)_(n) wherein Yis oxygen or sulfur and m and n independently of each other are aninteger of from 1 to 2, M is hydrogen or a metal selected from the groupconsisting of barium, calcium, and sodium, and the value of z is thesame as the available valence of M.
 20. A compound according to claim 19wherein R₁ and R₂ are each methyl.
 21. A compound according to claim 20wherein R₄ is straight-chain alkylene having 5 to 8 carbon atoms, or thegroup (CH₂)_(m) Y(CH₂)_(n) wherein Y is oxygen or sulfur and m and nindependently of each other are 1 and 2, and z has a value of 1 or 2.22. A compound according to claim 21 wherein M is hydrogen.
 23. Acompound according to claim 20 wherein R₄ is straight-chain alkylenehaving 5 to 8 carbon atoms.
 24. A compound according to claim 21 whereinR₄ wherein R₄ is the group (CH₂)_(m) Y(CH₂)_(n) and Y, m and n are asdefined in claim
 35. 25. A compound according to claim 21 which iso-mono-(2,2,6,6-tetramethyl-piperidin-4-ol)sebacate.
 26. A compoundaccording to claim 21 which is o-mono (1,2,2,6,6-pentamethylpiperidin-4-ol)diglycolate.